软土地基深基坑支护工程监测及变形特性分析

软土地基的复杂性及不定性是影响深基坑支护工程的重要因素.结合珠江三角洲某基坑地质条件较差的工程实例布置详细监测方案,并对基坑支护结构的水平位移、基坑地下水位、支撑轴力、基坑周边地表沉降的监测数据进行了综合分析,获得一些有价值的基坑变形规律.通过分析基坑支护结构及周边变形的因素,确保了基坑工程的施工质量以及周边建筑的安全.     

Spacecraft rendezvous trajectory safety quantitative performance index eliminating probability dilution

In view of the probability dilution problem of the existing quantitative indexes of rendezvous trajectory safety performance using collision probability,this paper proposes a new quantitative index of rendezvous trajectory safety performance by well combining collision probability with warning threshold.The proposed new index increases monotonously as the position errors of the chaser spacecraft increase,therefore it can effectively overcome the problems of the reduction in the largest performance value and the advancement in the most dangerous time induced by the probability dilution.The proposed new index is applied to the safety design of close range rendezvous missions.The mission’s safety requirements for initial navigation precision and the safe region of initial and final keeping points’positions with a certain navigation precision are analyzed,and several valuable conclusions about the relation between position navigation precision and velocity navigation precision as well as the relation between keeping points’positions and navigation precision are obtained.     

办公建筑物化阶段CO2排放研究

建筑物化阶段的CO2排放时间集中、绝对量大,是建筑节能减排的研究重点。构建了办公建筑物化阶段CO2排放的计算模型,包括建材、设备生产与运输的CO2排放,以及施工过程的CO2排放。利用该计算模型,分析计算了78栋办公建筑物化阶段的CO2排放量。平均来看,物化阶段的碳排放量为326.75kg/m2;随着建筑高度的增加单位面积碳排放明显增加,超高层建筑的单位面积碳排放量是多层建筑的1.5倍;土建工程的碳排放量占到物化阶段的75%左右,而钢筋、混凝土、砂浆、墙体材料的碳排放量占到了土建工程的80%以上。分别以建筑层数和建材用量为自变量做了办公建筑物化阶段CO2排放量的预测模型,通过统计学的分析对比,发现以钢筋、混凝土和墙体材料为自变量的预测公式可以很好地预测建筑物化阶段的碳排放。     

离网型风光互补发电系统多模态能量控制与管理

离网型风光互补发电系统是一种合理配置新能源的独立电源系统,由于自然界中风能、太阳能出现的不可预测性,以及负载、储能状态的随机性,提出一种基于风光互补发电系统多模态能量流的分析法,研究了各模态及模态间转化特性,给出了四种典型状态下风光互补发电系统的能量控制及管理。采用闭环电压控制使风力发电通道和光伏发电通道输出电压恒定,为用电设备和储能元件提供安全可靠的电能。通过MATLAB/Simulink软件对离网型风光互补发电系统多模态能量控制进行了仿真,结果表明离网型风光互补发电系统工作可靠,验证了多模态分析法的有效性。     

Effects of surface-activated coal gangue aggregates on properties of cement-based materials

Effects of calcined coal gangue （CG） aggregates treated by the surface thermal activation on the flowability and strength, and paste-CG aggregate interfaces of the cement-based material were investigated. The experimental results show that the compressive and flexural strength of the cement-based material with the calcined CG aggregates is much higher than that of the material with the natural CG aggregates, but the flowability of the material with calcined CG is significantly reduced with the calcined time. The strength of the material with the calcined CG aggregates only increases little with the calcined time at the same w/c ratio, but is reduced with the calcined time at the same flowability. The CG aggregates calcined by the surface thermal activation obviously overcomes the disadvantages of fully calcined CG.     

水热法制备锰锌铁氧体/碳纳米管磁性材料

采用成本低、污染少的水热法制备锰锌铁氧体包覆的碳纳米管磁性纳米复合材料,并对其进行表征.X射线衍射分析表明,180℃为制备复合材料的合适水温,所得粉体中含Mn0.5Zn05Fe2O4、碳纳米管和少量的γ-Fe2O3,升高反应温度并不能使γ-Fe2O3杂相消失.透射电镜及高分辨透射电镜分析表明,包覆在碳纳米管上的Mn0.5Zn0.5Fe2O4粒子为球形,粒径约为10 ～ 20 nm,Mn0.5Zn0.5Fe2O4粒子中含有少量方形的γ-Fe2O3.红外谱图分析表明,包覆前碳纳米管表面存在羟基、羰基和羧基等官能团,包覆后的复合材料在570 cm-1和1 388 cm-1处出现MnZn铁氧体的特征峰.磁滞回线结果表明,复合材料的饱和磁化强度值为1 145 364 A/m,剩余磁化强度值为438 517 A/m,矫顽力值为30 361 A/m,具有较好的铁磁性.     

一种配电网无功优化配置方法

在阐述配电网无功优化重要意义的基础上,该文分别对配电网无功优化配置实现过程中的重要环节进行论述。针对网损灵敏度法和无功二次精确矩法的不足,提出综合网损灵敏度法和无功二次精确矩法确定无功补偿点。该方法避免了传统单一方法优化中的局部集中,分布不均匀问题,使无功优化更合理可行。同时采用降低线损法结合遗传算法来获取补偿点的无功补偿容量。最后通过IEEE28算例对比分析,验证所提出方法是正确的并且适应于解决配电网实际情况。     

Degradation mechanism of lacquered tinplate in energy drink by in-situ EIS and EN

The corrosion process of phenolic epoxy coated tinplate in energy drink was investigated by in-situ electrochemical impedance spectroscopy(EIS) and electrochemical noise(EN) techniques. The experimental results indicate that the degradation process of novolac epoxy coated tinplate in energy drink can be divided into three main stages: organic coating wetted by the beverage; corrosion initiation beneath the organic coating; and corrosion extension process. It was proposed that the tin coating and carbon steel were mainly corroded by organic acids in energy drink through the pores of the organic coating. After the tin coating was corroded, the carbon steel started to corrode due to its higher electrochemical activity and became to be the dominated corrosion reaction.     

工业甲基萘及苊馏份三塔精馏过程的模拟和优化

工业甲基萘和工业苊都是重要的化工原料。工业甲基萘可以通过洗油直接精馏分离,工业苊主要通过精馏和结晶相结合的办法来提取。以脱萘之后的洗油为原料,用三炉三塔精馏,分别提取70%以上的工业甲基萘和55%以上的苊馏份,然后再通过结晶得到90%以上的工业苊。利用Aspen Plus软件工具,按照回流比最小,即消耗最低的原则对工业甲基萘和苊馏份的精馏过程进行详细模拟和优化,确定了3个精馏塔各物料最佳进料位置、最佳采出位置、采出量等。模拟结果与工业化实施结果基本一致。     

基于三角网格和模糊聚类的海洋牧场温度可视化

为了海洋牧场研究人员能直观地了解海水温度变化情况,对海洋牧场温度可视化进行了研究。在分析海洋牧场温度分布特点的基础上,提出用模糊聚类找到等温数据集,用Delaunay三角网构建技术生成海水等温面,用OpenGL图形接口绘制等温面的方法进行海洋牧场温度可视化。实验证明该方法运行速度快且无空洞现象发生。